1. Field of the Invention
The present invention relates to wireless communication techniques, and more particularly, to a wireless communication method and a beamformer capable of moderately selecting stations to be performed with beamforming.
2. Description of the Prior Art
With the popularity of wireless transmission applications such as using wireless fidelity (WiFi) to stream high definition movies and TV programs to a notebook, playing online games, browsing social media, or watching movies on a handheld device such as a tablet or a smart phone, a home user may concurrently download internet content using multiple WiFi devices. Increasing wireless transmission speed is therefore a trend in the field. Presently, some of wireless communication devices of which there operation frequency bands could be the same or overlap to each other, such as Bluetooth (BT) devices, cordless phones, and some 802.11b/g/n devices, which makes signal interference even more severe.
Beamforming is a technique applied to wireless transmissions. The beamforming technique calculates the influence of the channel on the receiver, and then compensates this influence at the transmitter in advance, thereby lowering the software and hardware requirements of the receiver to improve the transmission efficiency. Although the beamforming technique has been applied to the 802.11n system, the 802.11n specifications adopted by different manufacturers may not be compatible with each other.
The most current specification of the wireless local area network (WLAN) is 802.11ac. In contrast with 802.11n, the 802.11ac specifications adopted by different manufacturers are compatible with each other. Further, since the 802.11ac specifications operate on the 5 GHz frequency band which is less crowded than the 2.4 GHz frequency band, the possibility of multiple wireless devices sharing the same frequency band is decreased.
If there are multiple stations that have the beamforming function and are connected to the same beamformer (e.g. an access point) for performing wireless transmissions, the beamformer must store the channel state information (CSI) report of each channel connected to the beamformer, so that each station has the benefit of beamforming. The amount of hardware required for the beamformer to be capable of supporting beamforming needs to be increased, which raises the equipment cost and means the system loading will become heavier. The efficiency is therefore reduced.
In view of the above, how to effectively use the beamforming technique to raise the wireless transmission efficiency is an important issue in the field.